Liquid pump

ABSTRACT

A fluid pump, in particular a water pump, has a pump housing ( 11 ) that surrounds a pump wheel and a motor housing, connected to the pump housing, in which an electric motor ( 21 ) driving the pump wheel is received along with a stator ( 22 ) and rotor. For the sake of sealing off the pump from the escape of fluid and sealing off the motor housing from the penetration of fluid, with only one seal, and with assembly of the fluid pump without additional connecting elements, the pump housing ( 11 ) has a lower housing part ( 12 ) with an annular rib ( 14 ) protruding radially outward, and an upper housing part ( 13 ) slipped onto the lower housing part ( 12 ). Between the free annular face end of the upper housing part ( 13 ) and the annular rib ( 14 ), there is a sealing ring ( 15 ). The motor housing is embodied as a housing pot ( 26 ), which with a gripping edge ( 28 ) fits over the annular rib ( 14 ), sealing ring ( 15 ), and part of the upper housing part ( 13 ), and is locked to the upper housing part ( 13 ), producing an axial clamping force (FIG.  3 ).

BACKGROUND OF THE INVENTION

The invention is based on a fluid pump, in particular a water pump.

In such fluid pumps, there is a need to seal off the pump housing fromthe escape of fluid and to seal off the motor housing from thepenetration of fluid, such as splashing water, from the outside. To thatend, it is known, after the installation of the electric motor, to sealoff the motor housing in a manner proof against splashing water with ahousing cap, and to tightly cover the pump housing against the escape offluid by means of a cap flange and a sealing inlay. The pressure forcebetween the cap flange and the pump housing required for the tightconnection is achieved by screw connections, which are offset from oneanother by the same circumferential angles. The motor housing is securedto the cap flange, and the power takeoff shaft of the electric motor ispassed through the cap flange in a sealed fashion and in the interior ofthe pump housing receives the pump wheel in a manner fixed againstrelative rotation.

SUMMARY OF THE INVENTION

The fluid pump of the invention has the advantage that for sealing offthe pump housing and the motor housing, only one seal is needed, and thecontact-pressure force against the seal is generated without additionalfastening means. A single sealing using takes on both functions, thatis, seating off the pump housing from the escape of fluid and sealingoff the motor housing from the penetration of fluid from outside. Theassembly and disassembly of the pump are extremely simple and allow thecosts for production and repair to be dropped markedly. Since separatefastening means are not needed, the logistics of the assembly line canbe simplified and some assembly toots can be dispensed with, whichfurther contributes to lowering the production costs of the pump.

In an advantageous embodiment of the invention, the stator of theelectric motor and the lower housing part of the pump housing are fixedagainst one another nonrotatably, and the upper housing part and thelower housing part are positioned correctly relative to one another andheld nonrotatably against one another. This connection between thestator and the inner part of the housing on the one hand and the lowerand upper parts of the housing on the other, preferably performed by atongue and groove connection, serves on the one hand to provide anassembly code and on the other forms a relative-rotation preventer uponassembly, which assures a correct association of the stator, motorhousing and pump housing.

In an advantageous embodiment of the invention, the locking between thehousing pot and the upper housing part of the pump housing is embodiedlike a bayonet mount, and on the upper housing part it has protrudingretaining ribs, disposed equidistantly over the circumference of theupper housing part, and on the pot edge of the housing pot it hasundercuts, which can be brought into nonpositive and positive engagementwith one another by relative rotation of the housing pot and upperhousing part.

In an advantageous embodiment of the invention, an axially protrudingstop is disposed on the upper housing part, preferably on a retainingrib, and one of the undercuts strikes this stop at the end of therelative rotation, required for the locking, of the housing pot and thepump housing. This limitation of the relative rotary motion between thehousing pot and the pump housing is important so that the motor housingwill always have a defined position relative to the stator, and laterinstallation of the triggering electronics for the motor on the motorhousing can be accomplished without problems.

In an advantageous embodiment of the invention, a relative-rotationpreventer, which is operative once the locking has been established, isprovided between the housing pot and the upper housing part when theundercut contacts the stop of the upper housing part, and whichnonrotatably connects the housing pot and the pump housing to oneanother. This relative-rotation preventer assures that even in roughoperation, the connection between the upper housing part and the housingpot will not come loose unintentionally.

In an advantageous embodiment of the invention, the pot bottom of thehousing pot is provided with an oblong slot extending in thecircumferential direction, through which slot the winding terminals ofthe stator are passed. This oblong slot makes the relative rotationbetween the housing pot and the electric motor stator, which isconnected to the pump housing in a manner fixed against relativerotation, possible, which relative rotation is required for locking thehousing pot and the upper housing part of the pump housing. The oblongslot is covered by an electronics housing, in which the triggeringelectronics for the electric motor are integrated.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described in further detail in the ensuing descriptionin terms of an exemplary embodiment shown in the drawing. Shown are:

FIG. 1, a perspective view of a water pump;

FIG. 2, a back view of the water pump, in the direction of arrow II inFIG. 1;

FIG. 3, the water pump of FIG. 1 with the housing pot partly removed;

FIG. 4, a perspective view of the lower housing part of the pump housingwith the pump wheel and the electric motor, driving the pump wheel, ofthe water pump in FIG. 1;

FIG. 5, a detail showing a section taken along the line V—V in FIG. 1with the locking between the pump housing and the housing pot not yetaccomplished;

FIG. 6, a detail showing a section through the housing pot along theline VI—VI in FIG. 1, with the pump housing (not shown in section)locked to the housing pot.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The water pump, shown in perspective in FIG. 1 as an exemplaryembodiment for a fluid pump in general, is preferably used in motorvehicle construction in the cooling loop of the internal combustionengine or in the heating loop of the heating system. It has a two-partpump housing 11, which is composed of a lower housing part 12 and anupper housing part 13 slipped onto the lower housing part. The lowerhousing part 12, on its periphery, has a radially outward-protrudingannular rib 14, which serves as a support for the annular face end ofthe upper housing part 13 and for a sealing ring 15 slipped onto thejacket of the lower housing part 12 and located between the annular rib14 and the face end of the upper housing part 13. An axial intake neck16 surrounding an inlet opening 161 and an outlet neck 17 surrounding anoutlet opening 171 and extending at a tangent away are formed onto theupper housing part 13. One spiral channel 181, 182 is formed in each ofthe two housing parts 12, 13. The two channels 181, 182, which restcongruently on one another once the upper housing part 13 has beenslipped onto the lower housing part 12 form a pressure spiral 18 (FIG.5) that discharges into the intake neck 16.

In FIG. 4, only the channel 181 of the pressure spiral 18 embodied inthe lower housing part 12 can be seen; it is covered by the channel 182of the pressure spiral 18 that is embodied identically in the upperhousing part 13, and the outlet neck 17 on the pressure side is slippedover the edge of the orifice, which edge forms one half of the outletopening 171, of the lower channel 181 of the pressure spiral 18. A pumpwheel 19 is disposed coaxially with the axis of the pump housing 18 andis seated in a manner fixed against relative rotation on a power takeoffshaft 20 of an electric motor 21, which shaft protrudes coaxially intothe pump housing 11. The rotating pump wheel 19 aspirates water axiallyvia the intake neck 16 and pumps it into the pressure spiral 18, fromwhich the water flows out at pumping pressure via the outlet neck 17.

The electric motor 21, in a known manner, comprises a stator 22 (FIG. 4)and a rotor, not further shown here, which is surrounded annularly bythe stator 22. The stator 22 has a stator winding 23, which can besupplied with current via winding terminals 24, 25 (FIG. 2). Theelectric motor 21 is received in a housing pot 26, which fits over theannular rib 14 on the lower housing part 12, the sealing ring 15, andpart of the upper housing part 13, and which is locked to the upperhousing part 13 upon the establishment of an axial clamping forcebetween the upper housing part 12 and the housing pot 26. To that end,an annular bracing shoulder 27 (FIG. 5) for the annular rib 14 on thelower housing part 12 and a gripping edge 28 axially protruding past thebracing shoulder 27 are embodied on the pot opening 261 of the housingpot 26; when the housing pot 26 is placed on the pump housing 11, thegripping edge, with its inside face 281, slides over the annular rib 14,sealing ring 15, and a peripheral portion of the upper housing part 13,until the annular rib 14 strikes the bracing shoulder 27.

The housing pot 26, in its pot bottom 262 (FIG. 2), has an oblong slot29 extending in the circumferential direction, through which slot thewinding terminals 24, 25 of the stator winding 23 are passed. Althoughnot otherwise shown here, an electronics housing is mounted on the potbottom 261 and covers the oblong slot 29 and contains the triggeringelectronics, for instance for regulating the rotary speed, for theelectric motor 21 that are to be connected to the winding terminals 24,25.

As can be seen in FIGS. 1, 3, 5 and 6, the locking between the housingpot 26 and the upper housing part 13 is embodied like a bayonet mount,and on the upper housing part 13, it has retaining ribs 30, disposedequidistantly over the circumference, and undercuts 31 that are embodiedon the gripping edge 28. The retaining ribs 30 and undercuts 31 arebrought into engagement with one another by relative rotation of thehousing pot 26 and the upper housing part 13 of the pump housing 11, andas the relative rotation increases, an axial displacement motion ofthese two components ensues, which brings about a nonpositive pressingof the sealing ring 15 placed between the annular rib 14 and the faceend of the upper housing part 13.

The rotary motion is limited by a stop 32 (FIGS. 1 and 3), which isembodied on one of the retaining ribs 30 and protrudes axially into thepath of rotation of the undercuts 31. The established locking of thehousing pot 26 and the upper housing part 13 of the pump housing 11 isassured by a relative-rotation preventer 33 (FIGS. 1, 3 and 6). Therelative-rotation preventer 33 has an axially elastically deformable rib34, which protrudes outward from the upper housing part 13 and isdisposed between two successive retaining ribs 30 in such a way that itis deflected elastically by one of the undercuts 31 when the housing pot36 is being slipped onto the upper housing part 13. Once this undercut31 has rotated to in front of the associated retaining rib 30, the rib34 springs back again and places itself against the circumferentiallypointing end edge of the undercut 31, so that reverse rotation of thehousing pot 26 is prevented. A disassembly from the pump housing 11 andhousing pot 26 can be accomplished, by a contrary relative rotarymotion, only whenever the elastic rib 34 is lifted, with an auxiliarytool, out of the path of rotation of the undercuts 31.

The assembly of the water pump is performed as follows:

The sealing ring 15 embodied as an O-ring is mounted on the preassembledunit shown in FIG. 4, comprising the lower housing part 12, and theelectric motor 21 with stator 22, rotor and power takeoff shaft 20, andthis is done by slipping the sealing ring onto the jacket of the lowerhousing part 12 with slight expansion, until it contacts the annular rib14 of the lower housing part 12. As the sectional view in FIG. 5 shows,the stator 22 and the lower housing part 12 are secured against relativerotation to one another by a tongue and groove connection 35. Thistongue and groove connection 35 simultaneously serves as an assemblycode for the correct association in terms of rotary position of thestator 22 and the lower housing part 12.

The upper housing part 13 is slipped (FIG. 3) over the preassembledunit, including the sealing ring 15. The lower housing part 12 and theupper housing part 13 are fixed nonrotatably against one another by atongue and groove connection 36, which at the same time serves as anassembly code for the correct positioning of the upper housing part 13and the lower housing part 12 in the process of slipping the one ontothe other. Of the tongue and groove connection 36, all that can be seenin FIG. 4 is the axially extending groove in the lower housing part 12.

After the pump housing 11 has been put together, the housing pot 26 isslipped onto the stator 22 (FIG. 3), whereupon the gripping edge 28 atthe pot opening 261 increasingly fits over the annular rib 14, sealingring 15 and upper housing part 13, and the undercuts 31 slide along thegripping edge 28 between the retaining ribs 30 on the upper housing part13. In this process, the winding terminals 24, 25 of the stator winding23 pass through the oblong slot 29. The process of slipping the housingpot 26 on is concluded once the housing pot 27 and the lower housingpart 12 abut one another at the bracing shoulder 27. Now, by a rotarymotion of the housing pot 26, the undercuts 31 are rotated to in frontof the retaining ribs 30, the rotary motion being limited by the stop32. After the rotary motion of the housing pot 26, the sealing ring 15is axially compressed and reliably seals off not only the pump housing11 from the escape of water but also the housing pot 26 from thepenetration of water. If one undercut 31 strikes the stop 32 in therotary motion of the housing pot 26, then the rotary motion of thehousing pot 26 is blocked, and the rib 34, elastically deflected by anundercut 31, of the relative-rotation preventer 33 is released again bythe undercut 31, so that the rib 34 springs back into its originalposition and, by engaging the undercut 31 from behind, prevents areverse rotation of the housing pot 26 in the circumferential direction(FIGS. 1 and 6).

A bayonet mount is distinguished by the fact that the retaining ribs 30and/or undercuts 31 have an axial depth that increases in the directionof rotation, so that upon rotation of the two parts to be joinedtogether, an axial clamping force and thus a contact-pressure force onthe sealing ring 15 can be generated. Instead of being embodied withsuch a bayonet mount, the locking can be accomplished with retainingribs and undercuts of the kind that have a constant axial width orthickness. In that case, the axial association of the retaining ribs 30on the upper housing part 13 and the undercuts 31 on the housing pot 26must be done such that in the assembly process, before and during therotation of the housing pot 26 and pump housing 11, a pressure forcethat compresses the sealing ring 15 must be brought to bear, so that theundercuts 31 on the housing pot 26 can be rotated to in front of theretaining ribs 30 on the upper housing part 13.

1. A fluid pump, in particular a water pump, comprising: a pump housing(11) receiving a pump wheel (19); and a motor housing connected to thepump housing (11), in which motor housing an electric motor (21) thatdrives the pump wheel (19) is received along with a stator (22) androtor, wherein the pump housing (11) has a lower housing part (12), withan annular rib (14) protruding radially outward, and an upper housingpart (13) thrust onto the lower housing part (12), wherein between thefree, annular face end of the upper housing part (13) and the annularrib (14), a sealing ring (15) is disposed, and wherein the motor housingis embodied as a housing pot (26), which fits over the annular rib (14),the sealing ring (15), and part of the upper housing part (13) and islocked to the upper housing part (13), exerting an axial clamping force.2. The pump of claim 1, wherein an annular bracing shoulder (27) for theannular rib (14) on the lower housing part (12) and a gripping edge (28)protruding past the bracing shoulder (27) are embodied on the potopening (261) of the housing pot (26), and the gripping edge slides withits inside face (281) past the annular rib (14), the sealing ring (15),and a portion of the upper housing part (13).
 3. The pump of claim 1,wherein the stator (22) and the lower housing part (12) are positionedcorrectly relative to one another and fixed nonrotatably on one another,preferably via a positive-engagement connection (35).
 4. The pump ofclaim 1, wherein the upper housing part (13) and the lower housing part(12) are positioned correctly relative to one another and fixednonrotatably on one another, preferably via a positive-engagementconnection (35).
 5. The pump of claim 1, wherein the locking between thehousing pot (26) and the upper housing part (13) has retaining ribs(30), protruding from the upper housing part (13) and disposedequidistantly over the circumference of the upper housing part (13). andundercuts (31), embodied on the gripping edge (28), which can be broughtinto engagement with one another in the manner of a bayonet mount bymeans of relative rotation of the housing pot (26) and the upper housingpart (13).
 6. The pump of claim 5, wherein an axially protruding stop(32) is disposed on the upper housing part (13), preferably on the endof a retaining rib (30), and one of the undercuts (31) strikes this stopat the gripping edge (28) at the end of the relative rotation, requiredfor the locking, of the housing pot (26) and the pump housing (11). 7.The pump of claim 5, wherein a relative-rotation preventer (33), whichis operative after the establishment of the locking, is provided betweenthe housing pot (26) and the upper housing part (13).
 8. The pump ofclaim 7, wherein the relative-rotation preventer (33) has at least oneaxially elastically deformable rib (34), which protrudes from the upperhousing part (13) and is disposed such that when the housing pot (26) isslipped onto the upper housing part (13), this rib can be deflected byan undercut (31) sliding through between the retaining ribs (30), andafter rotation of the undercut (31), the rib springs back in front ofthe associated retaining rib (30) and rests on the end face pointing inthe circumferential direction of the undercut (30).
 9. The pump of claim1, wherein the stator (22) has winding terminals (24, 25) for electricalcontacting of a stator winding (23), and the housing pot (26) has anoblong slot (29), extending in the circumferential direction in the potbottom (262), through which slot the winding terminals (24, 25) extendfrom the housing pot (26).
 10. The pump of claim 9, wherein the oblongslot (29) has a length, measured in the circumferential direction, thatis greater than the rotation travel of the housing pot (26) relative tothe pump housing (11) connected to the stator (22) in a manner fixedagainst relative rotation.
 11. The pump of claim 1, wherein the pumphousing (11) has an inlet opening (161) coaxial with the pump wheel (19)on the intake side and an outlet opening (171) tangential to the pumpwheel (19) on the pressure side, in which outlet opening a pressurespiral (18) surrounding the pump wheel (19) discharges; and that thepressure spiral (18) is formed by two channels (181, 182), resting onone another, of which one is formed in the lower housing part (12) andone is formed in the upper housing part (13) of the pump housing (11).12. The pump of claim 11, wherein the inlet opening and outlet opening(161, 171) are each surrounded by one of two connection necks (16, 17)formed integrally onto the upper housing part (13).
 13. A fluid pump, inparticular a water pump, comprising: a pump housing (11) receiving apump wheel (19); and a motor housing connected to the pump housing (11),in which motor housing an electric motor (21) that drives the pump wheel(19) is received along with a stator (22) and rotor, wherein the pumphousing (11) has a lower housing part (12), with an annular rib (14)protruding radially outward, and an upper housing part (13) thrust ontothe lower housing part (12), wherein between the free, annular face endof the upper housing part (13) and the annular rib (14), a sealing ring(15) is disposed, wherein the motor housing is embodied as a housing pot(26), which fits over the annular rib (14), the sealing ring (15), andpart of the upper housing part (13) and is locked to the upper housingpart (13), exerting an axial clamping force, wherein the locking betweenthe housing pot (26) and the upper housing part (13) has retaining ribs(30), protruding from the upper housing part (13) and disposedequidistantly over the circumference of the upper housing part (13), andundercuts (31), embodied on the gripping edge (25), which can be broughtinto engagement with one another in the manner of a bayonet mount bymeans of relative rotation of the housing pot (26) and the upper housingpart (13), wherein a relative-rotation preventer (33), which isoperative after the establishment of the locking, is provided betweenthe housing pot (26) and the upper housing part (13), and wherein therelative-rotation preventer (33) has at least one axially elasticallydeformable rib (34), which protrudes from the upper housing part (13)and is disposed such that when the housing pot (26) is slipped onto theupper housing part (13), this rib can be deflected by an undercut (31)sliding through between the retaining ribs (30), and after rotation ofthe undercut (31), the rib springs back in front of the associatedretaining rib (30) and rests on the end face pointing in thecircumferential direction of the undercut (30).
 14. A fluid pump, inparticular a water pump, comprising: a pump housing (11) receiving apump wheel (19); and a motor housing connected to the pump housing (11),in which motor housing an electric motor (21) that drives the pump wheel(19) is received along with a stator (22) and rotor, wherein the pumphousing (11) has a lower housing part (12), with an annular rib (14)protruding radially outward, and an upper housing part (13) thrust ontothe lower housing part (12), wherein between the free, annular face endof the upper housing part (13) and the annular rib (14), a sealing ring(15) is disposed; and that the motor housing is embodied as a housingpot (26), which fits over the annular rib (14), the sealing ring (15),and part of the upper housing part (13) and is locked to the upperhousing part (13), exerting an axial clamping force, and wherein thesealing ring (15) rests against the upper housing part (13) and thelower housing part (12) of the pump housing (11) and the housing pot(26) of the motor housing.